Cutting instruments have been used for centuries by craftsmen, hunters, and others requiring a sharp cutting instrument. More recently, fixed length knives have been replaced with popular folding knives, which generally have two positions. In an open or extended position of use, the knife cutting blade is extended to expose the blade cutting edge and permit cutting therein. In a closed position, the cutting edge of the blade is stored within a cavity or recess in the handle portion of the knife, thus preventing the blade from being exposed. The folding knife further provides a cutting instrument which is much shorter in length than a typical fixed blade knife. Although these types of knives are extremely convenient, they can potentially become dangerous if the cutting blade does not have a locking mechanism to securely keep the knife blade in the first extended position of use. U.S. Pat. No. 6,751,868 discloses a folding knife with a substantially spherical locking mechanism, and is incorporated by reference herein in its entirety.
In particular, providing a locking mechanism comprising a strategically positioned two-piece backlock that engages the tang of the blade, which allows for travel between a first locked position and a second closed position without the need for other internal housing members, is desired.
Although there are other types of locking mechanisms used to prevent the inadvertent closure of a folding knife blade, such as a liner lock or a single piece backlock, many of these locking mechanisms are not simplistic to use, are expensive to manufacture, or are prone to failure. Thus, there is a need for a type of folding knife locking mechanism which overcomes these pitfalls and is simplistic to use, inexpensive to manufacture, and provides substantial strength to prevent any inadvertent failure. More specifically, by utilizing a toggle oriented to engage a stop surface of the blade tang, a folding knife with superior strength characteristics can be manufactured, and with improved compressive strength. There is also a need for an improved folding knife locking mechanism that is simplistic to assemble, uses a minimum number of components, and is extremely reliable to prevent the inadvertent closure of the knife blade. There is an additional need for a two-piece backlock that allows quick and easy manipulation by a user's thumb on the spine portion of the folding knife handle to assure quick closing.
U.S. Pat. No. 6,553,672 to Glesser et al. discloses a folding knife with a compression locking mechanism, and is incorporated by reference herein in its entirety. U.S. Pat. No. 6,918,184 to Glesser discloses a folding knife lock integral stop pin, and is incorporated by reference herein in its entirety. U.S. Pat. No. 6,751,868 to Glesser discloses a folding knife with a substantially spherical locking mechanism, and is incorporated by reference herein in its entirety. U.S. Pat. No. 5,615,484 to Pittman discloses a cam lock for a folding knife blade, and is incorporated by reference herein in its entirety. U.S. Pat. No. 4,985,998 to Howard discloses a folding knife with a blade lock, and is incorporated by reference herein in its entirety.